Method of forming transfemoral sockets and lock adapter therefor

ABSTRACT

A lock adapter is adapted to connect a residual limb liner with locking pin to a transfemoral prosthetic limb. The lock adapter is formed of a bracket having a first end and a second end, and preferably has a generally S-shaped configuration. The first end of the bracket has a first mounting face against which the lock is to be secured. The second end of the bracket is provided with a second mounting face against which the prosthetic limb is to be secured. The bracket being is formed so that the first and second mounting faces are spaced apart from one another, and may optionally be angled relative to one another. Methods of forming transfemoral test and final sockets are provided.

RELATED APPLICATION

This application is claiming the benefit, under 35 U.S.C. § 119(e), ofthe provisional application filed Jun. 15, 2001 under 35 U.S.C. §111(b), which was granted Ser. No. 60/298,541. This provisionalapplication is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The invention relates to prosthetic devices and methods of forming thesame. In particular, the invention relates to a method of forming bothtransfemoral test and finished thermosetting or laminated sockets, and alock adapter for connecting a residual limb transfemoral socket to alock mechanism and prosthetic knee joint.

A transfemoral prosthetic limb is conventionally secured to an amputee'sresidual limb stump by securing the prosthetic limb to a rigid socketassembly. This may commonly be done by through the use of a locking pin.In this technique, the amputee first dons a sock-like liner formed of anelastomer and may include fabric cover. The lower or distal end of theliner is formed of a rigid material, such as urethane, and the lockingpin extends from this rigid bottom. These liners are well known in theart. The pin is extended through the wall of the socket and a distaladapter mounted within or outside of the socket, and can be locked ontoa prosthetic lock mounted to the prosthetic limb to secure theprosthesis.

Typically, the pin has a longitudinal series of rack-like serrations andextends through a pin bore of the lock body. The teeth of a pinion gearin the lock body extend into the pin bore to engage the teeth of thelock pin therein. The pinion gear is mounted for one way rotation topermit entry of the lock pin into the pin bore but lock the lock pinagainst removal. The lock pin can be released only by moving the piniongear in a direction parallel to its rotational axis until it disengagesfrom the lock pin, e.g., via a manual release button.

In accordance with the conventional transfemoral sockets and attachmentlocking assemblies, a connecting mechanism is employed in which the lockin the socket is mounted in line with the prosthetic knee. In someamputees, especially those with mid to longer length above kneeamputations, this creates a gate disturbance as the knee center isdropped below the knee center of the sound limb. The conventionalconnecting mechanisms are further incapable of incorporating any flexionin the locking mechanism, which might beneficially accommodate the hipflexion contractures that are often associated with above kneeamputations.

Thus, it would advantageous to provide an improved transfemoral socketand lock adapter which allowed for a length off-set between the lock andthe prosthetic knee, and which further allowed for the desired degree offlexion, if any. It would further be advantageous to provide improvedmethods of forming test and finished transfemoral sockets using suchlock adapters.

SUMMARY OF THE INVENTION

The invention is directed to a lock adapter for connecting a residuallimb liner provided with a locking pin at its lower end that isreleasably engaged with a lock affixed to a transfemoral prostheticlimb. The lock adapter is formed of a bracket having a first end and asecond end, and preferably has a generally S-shaped configuration. Thefirst end of the bracket has a first mounting face against which thelock is to be secured. This first mounting face thus defines a firstlongitudinal axis that is perpendicular to the mounting face. The secondend of the bracket is provided with a second mounting face against whichthe prosthetic limb is to be secured. The second mounting face defines asecond longitudinal axis perpendicular thereto, and the bracket being isformed so that the first and second longitudinal axes are spaced apartfrom one another.

In addition, the bracket may optionally be formed so that the firstlongitudinal axis is angled relative to the second longitudinal axis.This configuration allows for the placement of a variety of degrees offlexion, preferably in a range greater than 0 degrees and less than orequal to 25 degrees.

The bracket may preferably be configured so that, in use, the first endof the bracket is forward of and below the second end of the bracket.This provides a length off-set between the lock and the prosthetic kneeso that the prosthetic knee center may be raised to the level of theknee center of the sound limb.

Any known lock adapted for use with the desired liner locking pin maybesecured to the first mounting face of the bracket. The lock may besecured to the first mounting face by any suitable means, such as by theuse of threaded fasteners, welding, adhesives or the like. In onepreferred embodiment, the lock is formed integrally with the first endof the bracket.

In another aspect, a method is provided for forming a transfemoral testsocket incorporating a lock in such a manner that the lock is removableand reusable. The method comprises providing a lock adapter assemblycomprising a bracket having a first end and a second end and a locksecured at the first end of the bracket, the lock being adapted toreleasably engage a locking pin of a residual limb liner. A lowerportion of the lock is masked with a masking material and the lockadapter assembly is fastened to a model of a portion of a residual limb.A polymeric transfemoral socket is then molded about the lock adapterassembly. Subsequently, the masking material is removed and the model isseparated from the socket. The masking material is preferably in theform of a fabrication block.

Further, a one-step method is provided for forming a transfemoral finalsocket, comprising providing a lock adapter assembly comprising abracket having a first end and a second end and a lock secured at thefirst end of the bracket, the lock being adapted to releasably engage alocking pin of a residual limb liner. The lock adapter assembly issecured to a model of a portion of a residual limb, and one or morefibrous reinforcing layers are positioned about the model and lockadapter assembly. A flowable polymeric resin is applied to the one ormore reinforcing layers to form a transfemoral socket about the modeland lock adapter assembly. The model is later separated from the socket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a somewhat schematic side elevational view, partially insection, of a thermoformed thermoplastic test socket connected to anartificial leg with a lock adapter in accordance with the invention.

FIG. 2 is an enlarged view, partially in section, of the device shown inFIG. 1.

FIG. 3 is a perspective of the lock adapter illustrated in FIG. 2.

FIG. 4 is an exploded perspective view of the lock adapter shown in FIG.2, the posterior foam filler and the fabrication block.

FIG. 5 is a perspective view of an alternate embodiment of the lockadapter of the invention.

FIG. 6 is a somewhat schematic side elevational view, partially insection, of a finished, thermosetting or laminated type transfemoralsocket connected to an artificial leg with a lock adapter in accordancewith the invention.

FIG. 7 is an enlarged view, partially in section, of the device shown inFIG. 6.

FIG. 8 is a perspective view of the lock adapter shown in FIG. 7.

FIG. 9 is an exploded perspective view of the lock adapter shown in FIG.7 and the fabrication block.

FIG. 10 is an exploded perspective view of another embodiment of thelock adapter with integral locking mechanism for a thermosetting resinor laminated type transfemoral socket.

FIG. 11 shows an exploded perspective view of still another embodimentof a lock adapter having an integral locking mechanism and integralpyramid adapter for use in a thermoplastic, transfemoral test socket.

FIG. 12 shows an exploded perspective view of an embodiment of a lockadapter having an integral locking mechanism and integral pyramidadapter for use in a thermosetting resin or laminated type transfemoralsocket.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 illustrates a lock adapter 5 ofthe present invention is used to connect and fabricate a residual limbtransfemoral socket 2 to a lock mechanism 4 and a knee joint 7. The lockadapter 5 is preferably of a generally S-shaped configuration, as shown.In the illustrated embodiment of FIG. 1, the prosthesis includes a pylon8 secured to the knee joint 7, the pylon 8 being in turn connected to anartificial foot 10 by means of the ankle assembly 9.

In the embodiment shown in FIG. 2, the transfemoral socket 2 has aposterior foam filler 3 to provide the shape of the distal posteriorinner aspect of the socket 2. The knee joint 7 is connected to the lockadapter 5 by means of suitable fasteners, such as four threaded holes15, best illustrated in the exploded view of the lock adapter 5 in FIG.4, with fastener screws. The lock adapter can be connected to the kneejoint 7 directly, or by means of an adapter, such as the pyramid adapter17. As illustrated, the conventional suction liner 1 is provided with alocking pin 6 that may be releasably engaged by the lock or lockingmechanism 4.

FIG. 3 is a perspective of the lock adapter of the invention. As shownin FIG. 3, the lock adapter 5 has threaded holes 12 which are used tofasten the lock adapter 5 to the transfemoral thermoplastic socket 2(FIG. 1) with, for example, machine screws 34. The cutout notchedcavities 11 are preferably included to provide for additional anchoringto the thermoplastic socket 2 (FIG. 1). The drilled through holes 13 areprovided to connect the lock mechanism 4 to the lock adapter 5 withfastener screws 36 (FIG. 4).

As further shown in FIG. 4 the posterior foam filler 3 has a cut outhole 3 a sized and shaped to allow the passage of the lock mechanism 4(FIG. 2). The fabrication block 38 is fastened to the lock adapter 5 viascrew holes 15 with the socket head cap screws 40. The set screws 30 areprovided to mark the location of the threaded screw holes 12 in thethermoplastic. The set screws 30 are removed after the thermoplasticsocket 2 (FIG. 1) is fabricated. The set screws 30 are then replacedwith washers 32 and socket head cap screws 34 to fasten the lock adapter5 to the thermoplastic socket 2 (FIG. 1).

A preferred method for fabricating the transfemoral test socket inaccordance with the present invention is as follows. A negative cast ismade of the residual limb and suction liner 1 (FIG. 1) with front andside alignment lines. This negative cast is filled with molding plasterand the fill pipe is set parallel to the alignment lines. After the moldhas set the negative cast material is removed and the result is apositive cast (not shown).

The positive cast will be used as a model for the transfemoral socket 2(FIG. 1). The positive cast is modified by adding or removing materialto achieve proper weight bearing in the transfemoral socket. Themodifications are done to the positive cast in accordance with standardprincipals of prosthetics. The positive cast may also be made by usingcomputer aided design and a computer lathe to manufacture the positivemold. The positive mold is painted with a mold sealer to reducemoisture.

A nylon is applied to the mold to provide a vacuum channel. The lockmechanism is fastened to the lock adapter with fastener screws 36through the attachment holes 13, as shown in FIG. 4. The fabricationblock 38 is attached to the lock adapter 5 at the four threaded holes 15with the socket head cap screws 40.

The posterior foam filler 3 is placed around the lock mechanism 4 andinside the support walls on the lock adapter 5, as shown in FIG. 2. Theset screws 30 (FIG. 4) are installed in the threaded holes 12 to markthe location in the thermoplastic socket. These set screws 30 are leftprotruding out of the lock adapter 5 an appropriate amount to mark thelocation of the holes 12.

The lock adapter 5 and lock mechanism 4 are attached to the positivemold with a fastener screw 18 through the center hole 14 in the lockadapter 5 and lock mechanism 4. The center hole 14 is preferably tappedso that various suction adapters and/or cosmetic adapters (not shown)may be threadedly attached thereto. Examples of suitable suctionadapters would include a plug to completely seal the center hole, a plugincorporating a one-way valve, and a lock pin cover.

The lock adapter 5 is positioned on the positive mold so that the lockmechanism 4 is horizontal to the fill pipe representing the negativecast alignment lines. The lock adapter 5 is positioned on the positivemold so that the knee joint 7 will have the amount of knee rotation asdetermined by the Prosthetist.

The thermoplastic sheet, cut to the appropriate size, is placed andheated in a wide oven at the appropriate forming temperature. Thepositive mold is placed horizontally in a vacuum fixture forthermoforming the plastic under negative pressure. The thermoplastic isremoved from the oven when the plastic is ready and moldable. Thethermoplastic sheet is applied to the positive mold. A seam is formedalong the lower aspect of the positive mold. The thermoplastic ispinched along the seam and held until the vacuum pulls in the plasticinto all the undercuts so that there are no air voids.

After the thermoplastic cools, the plastic is sanded down on top of thelock mechanism fastener screw 18. The fastener screw 18 is then removed.The fabrication block 38 is trimmed out, for example with a cast cutterand sanding router, and the four attachment screws 40 are removed alongwith the fabrication block 38.

The thermoplastic socket is removed from the positive mold usingcompressed air or the mold is broken out of the socket with, forexample, a pneumatic chisel. The thermoplastic socket material is sandeddown to the top of the set screws 30 using a sanding router. The setscrews 30 are removed with a hex wrench, and the fastener screws 34 withwashers 32 are installed and tightened in place of the set screws 30.

The edges of the thermoplastic socket material are sanded smooth. Thetransfemoral prosthesis is assembled with a knee joint 7, pylon 8, ankleassembly 9 and artificial foot 10, as illustrated in FIG. 1.

As shown in FIG. 5, the lock adapter 70 is provided with integrallocking mechanism 44 used to connect and fabricate the residual limbtransfemoral socket 2 (FIG. 1) to the knee joint 7. In this embodiment,at least a portion of the housing for the locking mechanism is formedintegrally with the lock adapter 70. The remainder of the lock adapteris the same as in the first embodiment. Thus, as shown in FIG. 5 thelock adapter 70 has threaded holes 72 which are used to fasten the lockadapter 70 to the transfemoral thermoplastic socket 2 (FIG. 1) withmachine screws 34. The cutout notched cavities 71 provide additionalanchoring to the thermoplastic socket 2 (FIG. 1).

As further shown in FIG. 5, the posterior foam filler 3 has a cut outhole 3 a to go around the lock mechanism 44. The fabrication block 38 isfastened to the lock adapter 70 via screw holes 75 with the socket headcap screws 40. The set screws 30 are again provided to mark the locationof the threaded screw holes 72 in the thermoplastic. The set screws 30are removed after the thermoplastic socket is fabricated. The set screws30 are replaced with washers 32 and socket head cap screws 34 to fastenthe lock adapter 70 to the thermoplastic socket 2 (FIG. 1).

A preferred method for fabricating the transfemoral socket with lockadapter with integral locking mechanism is as follows. A negative castis made of the residual limb and suction liner 1 (FIG. 1) with front andside alignment lines. This negative cast is filled with molding plasterand the fill pipe is set parallel to the alignment lines. After the moldhas set the negative cast material is removed and the result is apositive cast (not shown).

The positive cast will be used as a model for the transfemoral socket.The positive cast is modified by adding or removing material to achieveproper weight bearing in the transfemoral socket. The modifications aredone to the positive cast in accordance with standard principals ofprosthetics. The positive cast may also be made by using computer aideddesign and a computer lathe to manufacture the positive mold.

The positive mold is painted with a mold sealer to reduce moisture. Anylon is applied to the mold to provide a vacuum channel. Thefabrication block 38 is attached to the lock adapter 70 at the fourthreaded holes 75 with the socket head cap screws 40. The posterior foamfiller 3 is placed around the locking mechanism 44 and inside thesupport walls on the lock adapter 70.

The set screws 30 are installed in the threaded holes 72 to mark thelocation in the thermoplastic socket. These set screws are leftprotruding out of the lock adapter an appropriate amount to mark thelocation.

The lock adapter 70 with integral locking mechanism 44 are attached tothe positive mold with a fastener screw 18 through the center hole 74 inthe lock mechanism. The center hole 74 is preferably tapped so thatvarious suction adapters and/or cosmetic adapters (not shown) may bethreadedly attached thereto. Examples of suitable suction adapters wouldinclude a plug to completely seal the center hole, a plug incorporatinga one-way valve, and a lock pin cover.

The lock adapter 70 is positioned on the positive mold so that the lockadapter 70 is horizontal to the fill pipe representing the negative castalignment lines. The lock adapter 70 is positioned on the positive moldso that the knee joint 7 will have the amount of knee rotation asdetermined by the Prosthetist.

The thermoplastic sheet, cut to the appropriate size, is placed andheated in a wide oven at the appropriate forming temperature. Thepositive mold is placed horizontally in a vacuum fixture forthermoforming the plastic under negative pressure. The thermoplastic isremoved from the oven when the plastic is ready and moldable. Thethermoplastic sheet is applied to the positive mold. A seam is formedalong the lower aspect of the positive mold. The thermoplastic ispinched along the seam and held until the vacuum pulls in the plasticinto all the undercuts so that there are no air voids.

After the thermoplastic cools down the plastic is sanded down on top ofthe lock mechanism fastener screw 18. The fastener screw 18 is thenremoved. The fabrication block 38 is trimmed out with a cast cutter andsanding router and the four attachment screws 40 are removed along withthe fabrication block 38.

The thermoplastic socket is removed from the positive mold usingcompressed air, or the mold is broken out of the socket with a pneumaticchisel, or other suitable method is employed.

The thermoplastic socket material is sanded down to the top of the setscrews 30 using a sanding router. The set screws 30 are removed with ahex wrench, and the fastener screws 34 with washers 32 are installed andtightened in place of the set screws 30. The edges of the thermoplasticsocket material are sanded smooth. The transfemoral prosthesis isassembled with a knee joint 7, pylon 8, ankle assembly 9 and artificialfoot 10, as shown in FIG. 1.

As shown in FIG. 6, the lock adapter 21 of the present invention is usedto connect and fabricate a residual limb socket 20 to the lock mechanism4 and the knee joint 7. In the embodiment of FIG. 6, the prosthesisfurther includes a pylon 8 which is in turn connected to an artificialfoot 10.

The generally S-shaped lock adapter 21 of FIG. 7 is used during thefabrication of a laminated or thermosetting resin type socket. As shownin FIG. 8, a perspective view of the lock adapter 21, the lock adapter21 has through holes 23 used to fasten and reinforce the lock adapter 21to the transfemoral socket 1 using carbon fiber tape (not shown). Thecarbon fiber tape is threaded through the holes 23 during theapplication of the lay-up materials of stockinette for the lamination.The cutout or notched cavities 22 provide additional anchoring to thelaminated socket. The drilled through holes 63 are provided to connectthe lock mechanism 4 to the lock adapter 21 with fastener screws 36,shown in the exploded perspective view of FIG. 9.

As further shown in FIG. 9, the fabrication block 50 is fastened to thelock adapter 21 via screw holes 65 with the socket head cap screws 52.The knee joint 7 (FIG. 7) is connected to the lock adapter 21 throughthe four threaded holes 65 with fastener screws either directly, or witha pyramid adapter 17 (FIG. 7).

A preferred method of fabricating the laminated transfemoral socket inaccordance with the present invention is as follows. A negative cast ismade of the residual limb and suction liner 1 (FIG. 6) with front andside alignment lines. This negative cast is filled with molding plasterand the fill pipe is set parallel to the alignment lines. After the moldhas set the negative cast material is removed and the result is apositive cast (not shown).

The positive cast will be used as a model for the transfemoral socket.The positive cast is modified by adding or removing material to achieveproper weight bearing in the transfemoral socket. The modifications aredone to the positive cast in accordance with standard principals ofprosthetics. The positive cast may also be made by using computer aideddesign and a computer lathe to manufacture the positive mold.

The positive mold is painted with a mold sealer to reduce moisture. Anylon is applied to the mold to provide a vacuum channel. A polyvinylacetate (PVA) bag is installed as a separator from the resin.

The locking mechanism 4 shown in FIG. 7 is fastened to the lock adapter21 with fastener screws 36 (FIG. 9) through the attachment holes 63. Thefabrication block 50 is attached to the lock adapter 21 at the fourthreaded holes 65 with the socket head cap screws 52. The lock adapter21 and locking mechanism 4 are attached to the positive mold with afastener screw 18 through the center hole 64 in the lock adapter andlock mechanism. The center hole 64 is preferably tapped so that varioussuction adapters and/or cosmetic adapters may be threadedly attachedthereto. Examples of suitable suction adapters would include a plug tocompletely seal the center hole, a plug incorporating a one-way valve,and a lock pin cover.

The lock adapter 21 is positioned on the positive mold so that the lockadapter 21 is horizontal to the fill pipe representing the negative castalignment lines. The lock adapter 21 is positioned on the positive moldso that the knee joint 7 will have the amount of knee rotation asdetermined by the Prosthetist.

The positive mold is placed in a vacuum fixture for fabrication. A layerof Dacron™ polyester material is applied over the positive mold. TheDacron™ layer is trimmed off around the locking mechanism 4. Severallayers of the stockinette are applied to the positive model and trimmedaround the lock mechanism. The appropriate amount of stockinette layersare determined by the Prosthetist according to the age, weight andactivity level of the amputee.

Carbon tape reinforcement is applied through the through holes 23 of thelock adapter 21. The carbon fiber tape is generally sandwiched midwaybetween the layers of the appropriate layers of stockinette. Severaladditional layers of stockinette are applied over the complete lockingmechanism 4. The layers are twisted and reflected back over thelamination block 50. The appropriate amount of stockinette layers aredetermined by the Prosthetist according to the age, weight and activitylevel of the amputee.

The outer PVA bag is applied over the positive model and attached to thevacuum source to provide the negative pressure. The thermosetting resinis poured into the top of the PVA bag and the vacuum source draws resininto the layers of stockinette and carbon. The thermosetting resin ispulled into the stockinette and carbon material by the vacuum ornegative pressure during the lamination process. After the thermosettingresin sets and cools, the plastic resin is sanded down on top of thelocking mechanism fastener 18, and the fastener screw 18 is removed.

The fabrication block 50 is trimmed out with a cast cutter and sandingrouter and the four attachment screws 52 are removed along with thefabrication block. The laminated socket is removed from the positivemold using compressed air, or the positive mold is broken out of thesocket with a pneumatic chisel, or other suitable method is employed.The edges of the laminated socket material are sanded and buffed smooth.The transfemoral prosthesis is assembled with a knee joint 7, pylon 8,ankle assembly 9 and artificial foot 10, as shown in FIG. 6.

FIG. 10 shows an exploded perspective view of the lock adapter withintegral locking mechanism for a thermosetting resin or laminated typetransfemoral socket. In the alternate embodiment shown in FIG. 10, alock adapter 80 in accordance with the invention has an integral lockingmechanism 54 used to connect a residual limb socket 20 (see FIG. 6) tothe knee joint 7. The lock adapter 80 is used during the fabrication ofa laminated or thermosetting resin type final socket.

As shown in FIG. 10, the lock adapter 80 has through holes 93 used tofasten and reinforce the lock adapter 80 to the transfemoral socket withcarbon fiber tape (not shown). The carbon fiber tape is threaded throughthe holes 93 during the application of the lay-up materials ofstockinette for the lamination. The cutout or notched cavities 92provide additional anchoring to the laminated socket.

As further shown in FIG. 10, the fabrication block 50 is fastened to thelock adapter 80 via screw holes 85 with the socket head cap screws 52.The knee joint 7 is connected to the lock adapter 80 through the fourthreaded holes 85 with fastener screws, either directly or with apyramid adapter 17 (FIG. 7).

A preferred method for fabricating the laminated transfemoral socketwith lock adapter shown in FIG. 10 is as follows. A negative cast ismade of the residual limb and suction liner 1 (FIG. 6) with front andside alignment lines. This negative cast is filled with molding plasterand the fill pipe is set parallel to the alignment lines. After the moldhas set the negative cast material is removed and the result is apositive cast.

The positive cast will be used as a model for the transfemoral socket.The positive cast is modified by adding or removing material to achieveproper weight bearing in the transfemoral socket. The modifications aredone to the positive cast in accordance with standard principals ofprosthetics. The positive cast may also be made by using computer aideddesign and a computer lathe to manufacture the positive mold.

The positive mold is painted with a mold sealer to reduce moisture. Anylon is applied to the mold to provide a vacuum channel. A PVA bag isinstalled as a separator from the resin. The fabrication block 50 isattached to the lock adapter 80 at the four threaded holes 85 with thesocket head cap screws 52.

The lock adapter 80 and locking mechanism 54 are attached to thepositive mold with a fastener screw through the center hole 94 in thelocking mechanism 54. The lock adapter 80 is positioned on the positivemold so that the lock adapter 80 is horizontal to the fill piperepresenting the negative cast alignment lines. The lock adapter 80 ispositioned on the positive mold so that the knee joint 7 will have theamount of knee rotation as determined by the Prosthetist.

The positive mold is placed in a vacuum fixture for fabrication. A layerof Dacron™ material is applied over the positive mold. The Dacron™material is trimmed off around the lock mechanism. Several layers of thestockinette are applied to the positive model and trimmed around thelock mechanism. The appropriate amount of stockinette layers aredetermined by the Prosthetist according to the age, weight and activitylevel of the amputee. Carbon fiber tape reinforcement is applied throughthe through holes 93 of the lock adapter 80. The carbon fiber tape isgenerally sandwiched midway between the layers of the appropriate layersof stockinette. Several additional layers of stockinette are appliedover the complete locking mechanism. The layers are twisted andreflected back over the lamination block 50. The appropriate amount ofstockinette layers are determined by the Prosthetist according to theage, weight and activity level of the amputee.

The outer PVA bag is applied over the positive model and attached to thevacuum source to provide the negative pressure. The thermosetting resinis poured into the top of the PVA bag, and the vacuum source draws resininto the layers of stockinette and carbon fiber. The thermosetting resinis pulled into the stockinette and carbon material by the vacuum ornegative pressure during the lamination process. After the thermosettingresin sets and cools, the plastic resin is sanded down on top of thelock mechanism fastener screw 18, and the fastener screw is removed.

The fabrication block 50 is trimmed out with a cast cutter and sandingrouter and the four attachment screws 52 are removed along with thefabrication block. The laminated socket is removed from the positivemold using compressed air, or the positive mold is broken out of thesocket with a pneumatic chisel, or other suitable method is employed.The edges of the laminated socket material are sanded and buffed smooth.The transfemoral prosthesis is assembled with a knee joint 7, pylon 8,ankle assembly 9 and artificial, foot 10, as shown in FIG. 6.

FIG. 11 shows an exploded perspective view of a lock adapter having anintegral locking mechanism and integral pyramid adapter for use in athermoplastic, transfemoral test socket. As illustrated in FIG. 11, thelock adapter 100 with integral locking mechanism 45 is used to connect aresidual limb transfemoral socket 2 to the knee joint 7. A generallywedge-shaped posterior foam filler 3 is included to provide the shape ofthe distal posterior inner aspect of the socket 2. The knee joint 7 isconnected to the lock adapter 100 through the pyramid adapter 106, inthe same manner as is illustrated in FIG. 2.

As further shown in FIG. 11, the lock adapter 100 has threaded holes 102which are used to fasten the lock adapter 100 to the transfemoralthermoplastic socket with machine screws 34. The cutout notched cavities101 provide additional anchoring to the thermoplastic socket.

The posterior foam filler 3 has a cut out hole 3 a sized and shaped tofit about the locking mechanism 45. The fabrication block 38 is fastenedto the integral pyramid adapter 106 during fabrication of thethermoplastic socket. The set screws 30 are provided to mark thelocation of the threaded screw holes 102 in the thermoplastic. The setscrews 30 are removed after the thermoplastic socket is fabricated. Theset screws are replaced with washers 32 and socket head cap screws 34 tofasten the lock adapter to the thermoplastic socket.

A preferred method for fabricating the transfemoral socket of FIG. 11 isas follows. A negative cast is made of the residual limb and suctionliner 1 (FIG. 1) with front and side alignment lines. This negative castis filled with molding plaster and the fill pipe is set parallel to thealignment lines. After the mold has set the negative cast-material isremoved and the result is a positive cast.

The positive cast will be used as a model for the transfemoral socket.The positive cast is modified by adding or removing material to achieveproper weight bearing in the transfemoral socket. The modifications aredone to the positive cast in accordance with standard principals ofprosthetics. The positive cast may also, be made by using computer aideddesign and a computer lathe to manufacture the positive mold.

The positive mold is painted with a mold sealer to reduce moisture. Anylon is applied to the mold to provide a vacuum channel. Thefabrication block 108 is attached to the integral pyramid adapter 106 tofacilitate trimming out. The posterior foam filler 3 is placed aroundthe locking mechanism 45 and inside the support walls on the lockadapter 100.

The set screws 30 are installed in the threaded holes 102 to mark thelocation in the thermoplastic socket. These set screws are leftprotruding out of the lock adapter an amount sufficient to indicate thelocation.

The lock adapter 100 and locking mechanism 45 are attached to thepositive mold with a fastener screw 18 through the center hole 104 inthe lock mechanism. The lock adapter 100 is positioned on the positivemold so that the lock adapter 100 is horizontal to the fill piperepresenting the negative cast alignment lines. The lock adapter 100 ispositioned on the positive mold so that the knee joint 7 will have theamount of knee rotation as determined by the Prosthetist.

The thermoplastic sheet, cut to the appropriate size, is placed andheated in a wide oven at the appropriate forming temperature. Thepositive mold is placed horizontally in a vacuum fixture forthermoforming the plastic under negative pressure. The thermoplastic isremoved from the oven when the plastic is ready and moldable. Thethermoplastic sheet is applied to the positive mold. A seam is formedalong the lower aspect of the positive mold. The thermoplastic ispinched along the seam and held until the vacuum pulls in the plasticinto all the undercuts so that there are no air voids.

After the thermoplastic cools down, the plastic is sanded down on top ofthe lock mechanism fastener screw 18. The fastener screw 18 is thenremoved. The fabrication block 108 is trimmed out with a cast cutter andsanding router and the fabrication block is removed. The thermoplasticsocket is removed from the positive mold using compressed air, or themold is broken out of the socket with a pneumatic chisel, or othersuitable method is employed.

The thermoplastic socket material is sanded down to the top of the setscrews 30 using a sanding router. The set screws 30 are removed with ahex wrench, and the fastener screws 34 with washers 32 are installed andtightened in place of the set screws 30. The edges of the thermoplasticsocket material are sanded smooth. The transfemoral prosthesis is thenassembled with a knee joint 7 pylon 8, ankle assembly 9 and artificialfoot 10, in the manner shown in FIG. 1.

FIG. 12 shows an exploded perspective view of a lock adapter having anintegral locking mechanism and integral pyramid adapter for use in athermosetting resin or laminated type transfemoral socket. As shown inFIG. 12, the lock adapter 110 with integral locking mechanism 55 is usedto connect and fabricate a residual limb socket 20 to the knee joint 7in the manner shown in FIG. 6. In the illustrated embodiment, theprosthesis includes a pylon 8 which is in turn connected to anartificial foot 10. The lock adapter 110 of FIG. 12 is used during thefabrication of a laminated or thermosetting resin type socket.

As further shown in FIG. 12, the lock adapter 110 has through holes 112used to fasten and reinforce the lock adapter 110 to the transfemoralsocket with carbon fiber tape. The carbon fiber tape is threaded throughthe holes 112 during the application of the lay-up materials ofstockinette for the lamination. The cutout or notched cavities 111provide additional anchoring to the laminated socket.

FIG. 12 also shows the fabrication block 118 fastened to the integralpyramid adapter 116 during the fabrication of the socket. The knee joint7 is connected to the lock adapter 110 through the integral pyramidadapter 116.

A preferred method for fabricating the laminated transfemoral socket ofFIG. 12 is as follows. A negative cast is made of the residual limb andsuction liner 1 (FIG. 6) with front and side alignment lines. Thisnegative cast is filled with molding plaster and the fill pipe is setparallel to the alignment lines. After the mold has set the negativecast material is removed and the result is a positive cast.

The positive cast will be used as a model for the transfemoral socket.The positive cast is modified by adding or removing material to achieveproper weight bearing in the transfemoral socket. The modifications aredone to the positive cast in accordance with standard principals ofprosthetics. The positive cast may also be made by using computer aideddesign and a computer lathe to manufacture the positive mold.

The positive mold is painted with a mold sealer to reduce moisture. Anylon is applied to the mold to provide a vacuum channel. A PVA bag isinstalled as a separator from the resin.

The fabrication block 118 of FIG. 12 is attached to the integral pyramidadapter 116 to facilitate trimming out the plastic. The lock adapter 110and locking mechanism 55 are attached to the positive mold with afastener screw 18 through the center hole 114 in the locking mechanism.

The lock adapter 110 is positioned on the positive mold so that the lockadapter 110 is horizontal to the fill pipe representing the negativecast alignment lines. The lock adapter 110 is positioned on the positivemold so that the knee joint 7 will have the amount of knee rotation asdetermined by the Prosthetist.

The positive mold is placed in a vacuum fixture for fabrication. A layerof Dacron™ material is applied over the positive mold. The Dacron™material is trimmed off around the lock mechanism. Several layers of thestockinette are applied to the positive model and trimmed around thelock mechanism. The appropriate amount of stockinette layers aredetermined by the Prosthetist according to the age, weight and activitylevel of the amputee. Carbon fiber tape reinforcement is preferablyapplied through the through holes 112 of the lock adapter 110. Thecarbon fiber tape is generally sandwiched midway between the layers ofthe appropriate layers of stockinette. Several additional layers ofstockinette are applied over the complete locking mechanism. The layersare twisted and reflected back over the lamination block 118. Theappropriate amount of stockinette layers are determined by theProsthetist according to the age, weight and activity level of theamputee.

The outer PVA bag is applied over the positive model and attached to thevacuum source to provide the negative pressure; The thermosetting resinis poured into the top of the PVA bag and the vacuum source draws resininto the layers of stockinette and carbon. The thermosetting resin ispulled into the stockinette and carbon material by the vacuum ornegative pressure during the lamination process. After the thermosettingresin sets and cools down the plastic resin is sanded down on top of thelocking mechanism fastener screw 18, and the fastener screw 18 isremoved.

The fabrication block 118 is trimmed out with a cast cutter and sandingrouter and the fabrication block is removed. The laminated socket isremoved from the positive mold using compressed air, or the positivemold is broken out of the socket with a pneumatic chisel, or othersuitable method is employed.

The edges of the laminated socket material are sanded and buffed smooth.The transfemoral prosthesis is assembled with a knee joint 7, pylon 8,ankle assembly 9 and artificial foot 10

In accordance with the provisions of the patent statutes, the inventionhas been described in what is considered to represent its preferredembodiments. However, it should be noted that the invention can bepracticed otherwise than as specifically illustrated and describedwithout departing from its spirit or scope.

1. A lock adapter for connecting a residual limb liner provided with a locking pin at its lower end to a prosthetic limb, comprising: a bracket having a first end and a second end; and a lock secured at the first end of the bracket, the lock being adapted to releasably engage the locking pin of the liner; the second end of the bracket being adapted to have the prosthetic limb mounted thereto in such a manner that the longitudinal axis of the prosthetic limb is spaced apart from the longitudinal axis of the locking pin of the liner, and wherein the longitudinal axis of the prosthetic limb is positioned at an angle relative to the longitudinal axis of the locking pin of the liner that is greater than 0 degrees.
 2. A lock adapter as defined in claim 1, wherein the longitudinal axis of the prosthetic limb is positioned at an angle relative to the longitudinal axis of the locking pin of the liner that is greater than 0 degrees and less than or equal to 25 degrees.
 3. A lock adapter as defined in claim 1, wherein the bracket is generally S-shaped, with the first end of the bracket being adapted to be forward of and below the second end of the bracket in use.
 4. A lock adapter as defined in claim 1, wherein the lock is formed integrally with the first end of the bracket.
 5. A prosthetic device comprising a lock adapter for connecting a residual limb liner provided with a locking pin at its lower end that is releasably engaged with a lock affixed to a prosthetic limb, the lock adapter comprising a bracket having a first end and a second end, the first end of the bracket having a first mounting face against which the lock is secured so as to define a first longitudinal axis perpendicular to the first mounting face, and the second end of the bracket having a second mounting face against which the prosthetic limb is secured so as to define a second longitudinal axis perpendicular to the second mounting face, the bracket being formed so that the first and second longitudinal axes are spaced apart from one another.
 6. A lock adapter as defined in 5, wherein the bracket is formed so that the first longitudinal axis is positioned at an angle greater than 0 degrees relative to the second longitudinal axis.
 7. A lock adapter as defined in claim 5, wherein the first longitudinal axis is positioned at an angle relative to the second longitudinal axis that is greater than 0 degrees and less than or equal to 25 degrees.
 8. A lock adapter as defined in claim 5, wherein the bracket is generally S-shaped, with the first end of the bracket being adapted to be forward of and below the second end of the bracket in use.
 9. A lock adapter as defined in claim 5, wherein the lock is formed integrally with the first end of the bracket.
 10. A lock adapter as defined in claim 5, wherein the first mounting face is provided with a centrally located, tapped through-hole.
 11. A transfemoral prosthetic device comprising: a residual limb transfemoral socket having a sleeve, an open end adapted to receive a residual limb and a closed end having a through-hole formed therein for receiving a residual limb liner locking pin; a lock adapter assembly secured to the closed end of the socket, the lock adapter assembly including a generally S-shaped bracket having a first end and a second end and a lock secured at the first end of the bracket, the lock being adapted to releasably engage the locking pin of the liner; and a prosthetic knee joint secured to the second end of the bracket of the lock adapter assembly.
 12. A lock adapter for connecting a residual limb liner provided with a locking pin at its lower end to a prosthetic limb, comprising: a bracket having a first end and a second end; and a lock secured at the first end of the bracket, the lock being adapted to releasably engage the locking pin of the liner; the second end of the bracket being adapted to have the prosthetic limb mounted thereto in such a manner that the longitudinal axis of the prosthetic limb is spaced apart from the longitudinal axis of the locking pin of the liner, and wherein the bracket is generally S-shaped, with the first end of the bracket being adapted to be forward of and below the second end of the bracket in use. 